The takeaway
Si-Bone Inc shows a pronounced seasonal pattern over 8 years of data — strongest in December (+12.5%) and softest in March (−10.3%).
Right now
In July, the stock has fallen 29% of years, averaging −1.0%, roughly 3.1 pts behind the S&P 500.
The full picture
Si-Bone Inc's most dependable month has been December, higher in 8 of 8 years; March has been its least reliable, up just 14% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
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| 2018 | — | — | — | — | — | — | — | — | — |
Month by month
The stock's clearest edge over the S&P 500 lands in December (+11.5 pts); it has trailed the market most in March (−11.4 pts).
“vs S&P” is Si-Bone Inc’s average for a month minus the S&P 500’s average for that same month — isolating Si-Bone Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, December has closed higher 100% of the time versus 100% across the last 8 years — the pattern is weakening.
Figures are the typical (median) December return and how often it rose — the last 5 years versus the last 8(the heatmap’s default window). This verdict stays anchored to that 8-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
The seasonal story is really one month's story — December. It has closed higher in all 8 Decembers, a concentration the rest of the calendar can't touch.
The strength looks broad-based rather than freakish: its average (+12.5%) and median (+9.4%) sit close together, so no single blow-out year is flattering the figure. That reliability comes with real swings, mind — even December ranges by 9.2% from year to year, so any single year can land far from the average. Better still, that strength is the stock's own and not just a buoyant market — December has outpaced the S&P 500 by +11.5 points on average. Few peers keep such company in December — the typical stock clears it just 58% of the time.
It doesn't stand entirely alone — February and November have leaned firm as well, if less emphatically. The weaker half of the year is plainer: March has been the soft spot — the weakest of 5 months that average a loss (−10.3%), and the edge isn't year-round — the stock has trailed the S&P 500 in March, September, and October. Its roughest month on record was a −39.0% March in 2020 — a reminder of how hard even a seasonal name can fall.
December has now closed higher 8 years running. The pattern has softened of late, December's last five years slipping below its longer-run record.
For a stock this dependable in December, the sharper question is the rest of the year — outside its strong stretch, the calendar gives far less to lean on. With a short 8-year record and returns that swing hard year to year, the signal is best held loosely.
Short answers on the stock's best month (December), its worst (March), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2018 its best month (December, +12.5%) has run well ahead of its worst (March, −10.3%) — the heatmap above shows how steady that gap has been year to year.
December has been the strongest, averaging +12.5% and closing higher in all 8 years on record since 2018.
It's the weakest, averaging −10.3% — historically a soft spot, though it still varies from year to year.
Explore
These names have the strongest July track records on record — a starting point for comparison.
Before you trade